A known airbag device in the related art is configured to store a folded airbag in the upper part of a side wall inside a vehicle cabin, a vehicle-interior side portion thereof being covered with an airbag cover, and is configured to quickly inflate and deploy an airbag along the side wall inside the vehicle cabin, while reducing the amount by which the airbag projects toward the vehicle-interior side when inflated and deployed by folding the upper part and lower part of the airbag in different ways (see PTL 1).
FIG. 5 is a schematic cross-sectional view of this known head-protection airbag device in a folded state.
The above-described conventional airbag device includes an airbag 111 in a folded state, the airbag 111 being attached to the upper part of the side wall inside the vehicle cabin so as to extend in the vehicle front-rear direction; an airbag cover 108 that covers a vehicle-cabin-interior side portion of the airbag 111; and an inflator (not shown) that supplies gas to the airbag 111 to inflate and deploy the airbag downward inside the vehicle cabin.
The airbag 111 is stored in a space surrounded by the upper part of a pillar garnish 107, an inner panel 102 on the vehicle body side, and the airbag cover 108 in such a manner that it is wrapped in a wrapping member and is maintained in a folded shape. The airbag 111 includes an attachment portion 125 that has an attachment bracket 130 on the upper edge side thereof and is securely fixed to the inner panel 102 with an attachment bolt 131 inserted through this attachment bracket 130.
The airbag 111, in a stored state as shown in the figure, includes a roll-folded portion 138 formed by rolling the airbag 111 from the lower edge and a supply path portion 115 continuous with the roll-folded portion 138.
The supply path portion 115 is a portion into which inflation gas flows at the beginning of inflation of the airbag 111, the upper edge of the supply path portion 115 being disposed in the front-rear direction of the vehicle. As shown in the figure, the supply path portion 115 is provided with an inverted U-shaped portion 141 that is bent into an inverted U shape so as to cover the upper part of the roll-folded portion 138.
The inverted U-shaped portion 141 of the supply path portion 115 is formed such that a portion 115b located on the upper side when inflation and deployment are completed is located on a vehicle-exterior side O and a portion 115c located on the lower side when inflation and deployment are completed is located on a vehicle-interior side I.
The airbag cover 108 is disposed so as to cover a portion on the vehicle-interior side I of the folded and stored airbag 111 and, as shown by a dashed line in the figure, is pushed by the supply path portion 115, which is deployed at the beginning of inflation of the airbag 111, and is opened into the vehicle-interior side I to allow the airbag 111 to pass therethrough toward the vehicle-interior side I.
Because the conventional airbag 111 is configured as described above, when the inflation gas from the inflator is supplied to the supply path portion 115 at the time of inflation and deployment, the inverted U-shaped portion 141, which is disposed so as to wrap the upper part of the roll-folded portion 138, is inflated and deployed first. When the inverted U-shaped portion 141 is inflated and deployed, the roll-folded portion 138 is pushed downward in the figure due to the pressure and strikes an inclined upper end 107a of the pillar garnish 107. Subsequently, the roll-folded portion 138 enters the vehicle cabin through the cover 108, which has been pushed and opened by the inflating and deploying inverted U-shaped portion 141, and is deployed along the pillar garnish 107 while unfolding the roll fold rolled so as to be deployed toward the vehicle-exterior side O.
However, as has been described above, because this airbag device is configured such that the supply path portion 115, which is inflated at the initial stage of deployment, strongly pushes the roll-folded portion 138 downward at the beginning of inflation and deployment, causing it to strike the inclined upper end 107a of the pillar garnish 107, that is, such that the roll-folded portion 138 is caused to strike the inclined upper end 107a of the pillar garnish 107 before entering the vehicle-interior side I, there is a problem in that the speed at which it enters the vehicle cabin decreases correspondingly.